1.
National Monument (United States)
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Historically, some national monuments were managed by the War Department. National monuments can be so designated through the power of the Antiquities Act of 1906, President Theodore Roosevelt used the act to declare Devils Tower in Wyoming as the first national monument. The Antiquities Act of 1906 resulted from concerns about protecting mostly prehistoric Native American ruins, the Act authorized permits for legitimate archaeological investigations and penalties for taking or destroying antiquities without permission. Among the next three monuments he proclaimed in 1906 was Petrified Forest in Arizona, another natural feature, in 1908, Roosevelt used the act to proclaim more than 800,000 acres of the Grand Canyon as a national monument. In 1918, President Woodrow Wilson proclaimed Katmai National Monument in Alaska, Katmai was later enlarged to nearly 2,800,000 acres by subsequent Antiquities Act proclamations and for many years was the largest national park system unit. Petrified Forest, Grand Canyon, and Katmai were among the national monuments later converted to national parks by Congress. Substantial opposition did not materialize until 1943, when President Franklin D. Roosevelt proclaimed Jackson Hole National Monument in Wyoming. He did this to accept a donation of lands acquired by John D. Rockefeller, roosevelts proclamation unleashed a storm of criticism about use of the Antiquities Act to circumvent Congress. A bill abolishing Jackson Hole National Monument passed Congress but was vetoed by Roosevelt, the proclamation authority was not used again anywhere until 1996, when President Bill Clinton proclaimed the Grand Staircase-Escalante National Monument in Utah. This action was unpopular in Utah, and bills were introduced to further restrict the presidents authority. To date, none of them have been enacted, presidents have used the Antiquities Acts proclamation authority not only to create new national monuments but to enlarge existing ones. For example, Franklin D. Roosevelt significantly enlarged Dinosaur National Monument in 1938, lyndon B. Johnson added Ellis Island to Statue of Liberty National Monument in 1965, and Jimmy Carter made major additions to Glacier Bay and Katmai National Monuments in 1978. Marine National Monument List of U. S. National Forests List of areas in the National Park System of the United States List of U. S
2.
Natural Bridges National Monument
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Natural Bridges National Monument is a U. S. It features the thirteenth largest natural bridge in the world, carved from the white Permian sandstone of the Cedar Mesa Formation that gives White Canyon its name, the three bridges in the park are named Kachina, Owachomo, and Sipapu, which are all Hopi names. A natural bridge is formed through erosion by flowing in the stream bed of the canyon. Eventually, as erosion and gravity enlarge the opening, the bridge collapses under its own weight. There is evidence of at least two collapsed natural bridges within the Monument, in 1904, the National Geographic Magazine publicized the bridges and the area was designated a National Monument April 16,1908 by President Theodore Roosevelt. It is Utahs first National Monument, the Monument was nearly inaccessible for many decades, as reflected by the visitor log kept by the Monuments superintendents. The bridges and other features present on the Colorado Plateau today were molded by the processes of erosion, the destructive forces of wind and rain, running water, and freezing temperatures attacked the uplifts as soon as all the tectonic havoc started in the Late Cretaceous. The Colorado Plateau has been uplifted about 12,000 feet since the end of the Cretaceous about 66 million years ago, some of this uplift occurred geologically rapidly. As the rate of uplift increased, so did the rate of erosion, the Colorado River, for example, carved its present course within the last 6 million years. The Monuments elevation ranges up to 6,500 feet, the Monuments vegetation is predominantly pinyon-juniper forest, with grass and shrubs typical of high-elevation Utah desert. In the canyons, where there is water and seasonal streams, riparian desert plants, such as willow, oak and cottonwood trees. Because the Monument has been closed to grazing for nearly a century, potential bridge collapse is possible at Natural Bridges National Monument, especially along the span of Owachomo Bridge in Armstrong Canyon which is only 9 feet thick at the crest of its span. Earthquake potential is high along the Moab Fault in nearby Arches National Park, while this and other faults in the Paradox Basin are associated with salt structures, the Colorado Plateau interior does possess a low level of seismic hazard. Ground shaking from earthquakes may impact the bridges at Natural Bridges National Monument causing catastrophic failure of one or more of the bridges, there is also a campground and picnic areas within the park. Electricity in the park entirely from a large solar array near the visitors center. To date, Natural Bridges has the only night sky monitored by the NPS Night Sky Team that rates a Class 2 on the Bortle Dark-Sky Scale, horsecollar Ruin is an Ancestral Puebloan ruin visible from an overlook a short hike from Bridge View Drive. The Monuments pygmy rattlesnakes have been the subject of occasional study, in May 2006, KSL Newsradio reported a case of plague found in dead field mice and chipmunks at Natural Bridges. Invasive species include tumbleweeds, certain thistles, dandelions, and tamarisk, much of the monuments ground is covered in communities of cryptobiotic soil crusts, which prevents soil erosion and promotes retention of soil nutrients
3.
Natural Bridge Caverns
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The span was left suspended when a sinkhole collapsed below it. The caverns are located near the city of San Antonio, Texas in the Texas Hill Country next to the Natural Bridge Wildlife Ranch, the caverns feature several unique speleothems and other geological formations. The temperature inside the cave is 21 degrees Celsius year-round and the humidity rate is a constant 99 percent, the deepest part of the public tour is 180 feet below the surface, although undeveloped areas of the cavern reach depths of 230 feet. The caverns are still active and considered living. After exiting the limestone, water enters the caverns where it flows and drips constantly throughout, the caverns were discovered on March 27,1960, by students Orion Knox Jr. Preston Knodell Jr. Al Brandt and Joe Cantu from St. Marys University in nearby San Antonio. On their fourth trip into the caverns, the men discovered/explored just over a mile of passage, subsequent explorations revealed 2 miles associated with what became known as the North Cavern. After discovery, Orion Knox Jr. assisted the landowners in obtaining information, Mrs. Clara Wuest, wanted to show the world the cave under her property. Orion approached both the National Park Service and the Texas Park System, while both entities agreed that the cavern was substantial and merited development, both groups told the landowners that funds did not exist for their respective groups to undergo such an endeavor. Mrs. Wuest then decided that she would fund development, Orion dropped out of school to assist. He also approached Jack Burch who had just finished work on developing the Caverns of Sonora near Sonora, Jack agreed to help and development began early in 1963. Mrs. Wuest remarried Harry Heidemann, a retired Texas Highway Patrolman in the early 1960s, together, they started work on developing the cavern. The full-time development crew included Mrs. Wuest-Heidemann, Mr. Heidemann, Jack Burch, Orion Knox, development on the cavern began in 1963 and work on lights and trails continued until opening day, July 3,1964. The cavern has been opened ever since and is owned and operated by family members. Natural Bridge Caverns became a registered United States National Natural Landmark in 1971. During excavation of the trail, a human tooth, arrowheads. Also, just inside the entrance, a jawbone and femur from a species of black bear were discovered. This leads many to believe that uppermost areas of the cavern were used as a shelter by early peoples, an archaeological dig was recently done under the natural bridge. Archaeologists recovered arrow heads and other tools which further indicate the presence of peoples at some point in history. In 1967, speculation on a southern extent to the North Cavern was confirmed when test drilling indicated the presence of a large void approximately 90 feet beneath the surface, a camera was sent down the narrow shaft and photographs revealed a large chamber filled with formations
4.
Delicate Arch
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Delicate Arch is 65-foot-tall freestanding natural arch located in Arches National Park near Moab, Utah, USA. The Olympic torch relay for the 2002 Winter Olympics passed through the arch, because of its distinctive shape, the arch was known as the Chaps and the Schoolmarms Bloomers by local cowboys. It was given its current name by Frank Beckwith, leader of the Arches National Monument Scientific Expedition, in the 1950s, the NPS investigated the possibility of applying a clear plastic coating to the arch to protect it from further erosion and eventual destruction. The idea was abandoned as impractical and contrary to NPS principles. Delicate Arch is formed of Entrada Sandstone, the original sandstone fin was gradually worn away by weathering and erosion, leaving the arch. Other arches in the park were formed the same way but, due to placement, during the summer, white-throated swifts nest in the top of the arch. Nature photographer Michael Fatali started a fire under the arch in September 2000 to demonstrate nighttime photography techniques to a group of amateur photographers, the fire discolored portions of the sandstone near the arch. Fatali was placed on probation and fined $10,900 in restitution to the NPS for the cost of cleanup efforts, in May 2006, climber Dean Potter made the first recorded free solo – no ropes or protection – ascent of this formation. Climbing Delicate Arch was not explicitly forbidden under the rules in force at the time and it was understood, however, that the named-arch formations should not be climbed. The NPS has since closed the loophole by disallowing climbs on any named arch within the park year-round, slacklining and the placement of new fixed anchors on new climbs is also prohibited. Controversy erupted when photographs taken after Potters climb appeared to damage caused by a climbing technique called top roping. Potter stated on several occasions that he never top-roped the arch and it is possible that a previous climber had top-roped the arch, leaving the existing rope scars. Arches National Park Trails Page Arches National Park homepage Panorama Under Arch Beautiful Places episode of Delicate Arch Panoramic View of Delicate Arch at Sunset
5.
Arches National Park
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Arches National Park is a US National Park in eastern Utah. The park is adjacent to the Colorado River,4 miles north of Moab and it is home to over 2,000 natural sandstone arches, including the world-famous Delicate Arch, in addition to a variety of unique geological resources and formations. It contains the highest density of natural arches in the world, the park consists of 76,679 acres of high desert located in the Colorado Plateau. Its highest elevation is 5,653 feet at Elephant Butte, forty-three arches are known to have collapsed since 1977. The park receives on average 10 inches of rain a year, administered by the National Park Service, the area was originally named a National Monument on April 12,1929. It was redesignated as a National Park on November 12,1971, over millions of years, the salt bed was covered with debris eroded from the Uncompahgre Uplift to the northeast. During the Early Jurassic desert conditions prevailed in the region and the vast Navajo Sandstone was deposited, an additional sequence of stream laid and windblown sediments, the Entrada Sandstone, was deposited on top of the Navajo. Over 5,000 feet of sediments were deposited and have been mostly eroded away. Remnants of the cover exist in the area including exposures of the Cretaceous Mancos Shale, the arches of the area are developed mostly within the Entrada formation. The weight of this caused the salt bed below it to liquefy. The evaporites of the area formed more unusual salt anticlines or linear regions of uplift, faulting occurred and whole sections of rock subsided into the areas between the domes. In some places, they turned almost on edge, the result of one such 2, 500-foot displacement, the Moab Fault, is seen from the visitor center. As this subsurface movement of salt shaped the landscape, erosion removed the rock layers from the surface. Except for isolated remnants, the formations visible in the park today are the salmon-colored Entrada Sandstone, in which most of the arches form. These are visible in layer cake fashion throughout most of the park, over time, water seeped into the surface cracks, joints, and folds of these layers. Ice formed in the fissures, expanding and putting pressure on surrounding rock, breaking off bits, winds later cleaned out the loose particles. A series of free-standing fins remained, wind and water attacked these fins until, in some, the cementing material gave way and chunks of rock tumbled out. Others, with the degree of hardness and balance, survived despite their missing sections
6.
Utah
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Utah is a state in the western United States. It became the 45th state admitted to the U. S. on January 4,1896, Utah is the 13th-largest by area, 31st-most-populous, and 10th-least-densely populated of the 50 United States. Utah has a population of more than 3 million, approximately 80% of whom live along the Wasatch Front, Utah is bordered by Colorado to the east, Wyoming to the northeast, Idaho to the north, Arizona to the south, and Nevada to the west. It also touches a corner of New Mexico in the southeast, approximately 62% of Utahns are reported to be members of The Church of Jesus Christ of Latter-day Saints or LDS, which greatly influences Utahn culture and daily life. The LDS Churchs world headquarters is located in Salt Lake City, Utah is the only state with a majority population belonging to a single church. The state is a center of transportation, education, information technology and research, government services, mining, in 2013, the U. S. Census Bureau estimated that Utah had the second fastest-growing population of any state. St. George was the metropolitan area in the United States from 2000 to 2005. Utah also has the 14th highest median income and the least income inequality of any U. S. state. A2012 Gallup national survey found Utah overall to be the best state to live in based on 13 forward-looking measurements including various economic, lifestyle, the name Utah is derived from the name of the Ute tribe. It means people of the mountains in the Ute language, according to other sources Utah is derived from the Apache name Yudah which means Tall. These Native American tribes are subgroups of the Ute-Aztec Native American ethnicity and were sedentary, the Ancestral Pueblo people built their homes through excavations in mountains, and the Fremont people built houses of straw before disappearing from the region around the 15th century. Another group of Native Americans, the Navajo, settled in the region around the 18th century, in the mid-18th century, other Uto-Aztecan tribes, including the Goshute, the Paiute, the Shoshone, and the Ute people, also settled in the region. These five groups were present when the first European explorers arrived, the southern Utah region was explored by the Spanish in 1540, led by Francisco Vásquez de Coronado, while looking for the legendary Cíbola. A group led by two Catholic priests—sometimes called the Dominguez-Escalante Expedition—left Santa Fe in 1776, hoping to find a route to the coast of California, the expedition traveled as far north as Utah Lake and encountered the native residents. The Spanish made further explorations in the region, but were not interested in colonizing the area because of its desert nature, in 1821, the year Mexico achieved its independence from Spain, the region became known as part of its territory of Alta California. European trappers and fur traders explored some areas of Utah in the early 19th century from Canada, the city of Provo, Utah was named for one, Étienne Provost, who visited the area in 1825. The city of Ogden, Utah was named after Peter Skene Ogden, in late 1824, Jim Bridger became the first known English-speaking person to sight the Great Salt Lake. Due to the salinity of its waters, Bridger thought he had found the Pacific Ocean
7.
Rock formation
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A rock formation is an isolated, scenic, or spectacular surface rock outcrop. Rock formations are usually the result of weathering and erosion sculpting the existing rock, the term rock formation can also refer to specific sedimentary strata or other rock unit in stratigraphic and petrologic studies. Erosion later exposes them in their current form, an example is Bryce Canyon National Park in Utah. Metamorphic rocks are created by rocks that have transformed into another kind of rock, usually by some combination of heat, pressure. An example are the Seneca Rocks in West Virginia, igneous rocks are created when molten rock cools and solidifies, with or without crystallization. They may be either plutonic bodies or volcanic extrusives, again, erosive forces sculpt their current forms. An example is Half Dome in Yosemite National Park, geologists have created a number of terms to describe different rock structures in the landscape that can be formed by natural processes, Inselberg or monadnock is a residual relief feature. It can be a hill, a knob, ridge or small mountain that rises abruptly, like an island. Inselberg is a German word that means island mountain, uluru/Ayers Rock in Australia is a noted example. Peak Stack Mesa Butte Escarpment Gorge Sea cliff River cliff Stone run Crag Tor Promontory is a prominent mass of land which overlooks lower lying land or a body of water, here is a list of rock formations by continent
8.
Arch
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An arch is a curved structure that spans a space and may or may not support weight above it. Arch may be synonymous with vault, but a vault may be distinguished as a continuous arch forming a roof, an arch is a pure compression form. It can span an area by resolving forces into compressive stresses and. This is sometimes referred to as arch action, as the forces in the arch are carried to the ground, the arch will push outward at the base, called thrust. As the rise, or height of the arch decreases, the outward thrust increases, in order to maintain arch action and prevent the arch from collapsing, the thrust needs to be restrained, either with internal ties or external bracing, such as abutments. The most common true arch configurations are the arch, the two-hinged arch. The fixed arch is most often used in reinforced concrete bridge and tunnel construction, because it is subject to additional internal stress caused by thermal expansion and contraction, this type of arch is considered to be statically indeterminate. The two-hinged arch is most often used to long spans. This type of arch has pinned connections at the base, unlike the fixed arch, the pinned base is able to rotate, allowing the structure to move freely and compensate for the thermal expansion and contraction caused by changes in outdoor temperature. However, this can result in additional stresses, so the two-hinged arch is also statically indeterminate, the three-hinged arch is not only hinged at its base, like the two-hinged arch, but at the mid-span as well. The additional connection at the mid-span allows the arch to move in two opposite directions and compensate for any expansion and contraction. This type of arch is not subject to additional stress caused by thermal change. The three-hinged arch is said to be statically determinate. It is most often used for structures, such as large building roofs. Another advantage of the arch is that the pinned bases are more easily developed than fixed ones, allowing for shallow. Arches have many forms, but all fall into three categories, circular, pointed, and parabolic. Arches can also be configured to produce vaults and arcades, Arches with a circular form, also referred to as rounded arches, were commonly employed by the builders of ancient, heavy masonry arches. Ancient Roman builders relied heavily on the arch to span large
9.
Cliff
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In geography and geology, a cliff is a vertical, or nearly vertical, rock exposure. Cliffs are formed as erosion landforms by the processes of weathering, Cliffs are common on coasts, in mountainous areas, escarpments and along rivers. Cliffs are usually formed by rock that is resistant to weathering, sedimentary rocks most likely to form cliffs include sandstone, limestone, chalk, and dolomite. Igneous rocks such as granite and basalt also often form cliffs, an escarpment is a type of cliff, formed by the movement of a geologic fault or a landslide. Most cliffs have some form of slope at their base. In arid areas or under high cliffs, they are generally exposed jumbles of fallen rock, in areas of higher moisture, a soil slope may obscure the talus. Many cliffs also feature tributary waterfalls or rock shelters, sometimes a cliff peters out at the end of a ridge, with tea tables or other types of rock columns remaining. Coastal erosion may lead to the formation of sea cliffs along a receding coastline, the Ordnance Survey distinguishes between cliffs and outcrops. Cliff is a Romance loanword that has its origins in the Latin forms clivus / clevus. Given that a cliff need not be vertical, there can be ambiguity about whether a given slope is a cliff or not. For example, given a vertical rock wall above a very steep slope. Listings of cliffs are thus inherently uncertain, some of the largest cliffs on Earth are found underwater. For example, an 8,000 m drop over a 4,250 m span can be found at a ridge sitting inside the Kermadec Trench. One candidate for highest cliff in the world is Nanga Parbats Rupal Face, according to other sources, the highest cliff in the world, about 1,340 m high, is the east face of Great Trango in the Karakoram mountains of northern Pakistan. The location of the worlds highest sea cliffs depends also on the definition of cliff that is used, guinness World Records states it is Kalaupapa, Hawaii, at 1,010 m high. Another contender is the face of Mitre Peak, which drops 1,683 m to Milford Sound. These are subject to a less stringent definition, as the slope of these cliffs at Kaulapapa is about 1.7, corresponding to an angle of 60 degrees. A more vertical drop into the sea can be found at Maujit Qaqarssuasia which is situated in the Torssukátak fjord area at the tip of South Greenland
10.
Cliffed coast
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A cliffed coast, also called an abrasion coast, is a form of coast where the action of marine waves has formed steep cliffs that may or may not be precipitous. It contrasts with a flat or alluvial coast, the slope is constantly being eroded. The waves attacking the cliff-foot form a notch by constant abrasion action producing an overhang. This overhang grows in size as the cliff is undercut, until it collapses under its own weight, the loose debris that has broken off is gradually carried away from the area in front of the cliff by the action of the sea. As the coastal cliffs collapse, the shoreline recedes inland, the speed at which this happens depends, in particular, on the strength of the surf, the height of the cliff, the frequency of storm surges and the hardness of the bedrock. Thus, the Mecklenburg coast in Germany recedes by about 25 centimetres per year, whereas the chalk cliffs of southern England retreat by just ½ a centimetre each year. A cliffed coast is made of a loose material, such as at the Red Cliff on the German island of Sylt. There are, however, differences between the former and the latter regarding some peculiarities of the coast line and it represents the foot of the cliff preserved at and below the level of water table. On a cliffed coast made up of material which is only fairly or even hardly resistant to erosion no wave-cut platform, if waves carve notches at a narrow point on both sides of a promontory on the rocky cliffed coast, a natural arch may be formed. When the arch collapses as the coastline recedes further a stack is left behind on the wave-cut platform, the best-known example in Germany is the Lange Anna on Heligoland. Furthermore, on a rocky cliffed coast wave action is not the driving force for coastline retreat. General weathering of the bedrock is almost equally important, living cliffs are those on a coast that is still active, i. e. that is being eroded and is receding. A dead cliff, by contrast, is reached by very high marine waves and is therefore subjected to very little change. A clear indication of a lack of activity at a cliff is a covering of vegetation that appears on the cliff as wave action against it subsides. Well-known coasts with living cliffs in Germany are the Red Cliff in Kampen on the island of Sylt or the cliffs on the Jasmund Peninsula. The Königsstuhl on the island of Rügen is an example of a dead cliff. Others may be found in the regions of the present-day Wadden Sea coast of the North Sea a few kilometres inland and these show the former coastline from which the sea retreated as the level of water in the North Sea fell. Steep sea cliffs can also be caused by catastrophic debris avalanches and these have been common on the submerged flanks of ocean island volcanos such as the Hawaiian Islands and the Cape Verde Islands
11.
Fin (geology)
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Fins are narrow, residual walls of hard sedimentary rock that remain upright after adjacent rock has been eroded away along systematic parallel joints or fractures on either side. A fin is formed when a narrow butte or plateau develops a series of vertical cracks in a parallel pattern. Differential water erosion, sometimes as part of a freeze-thaw cycle, where two or more fins are present, a slot canyon may be formed between them. A wall left standing in between two slot canyons may be termed a fin, alternatively, an entirely isolated single fin may develop where a rock stratum is notably harder relative to neighboring strata. Myriads of fins, and more advanced features, may be seen at Arches National Park in Utah. Rock fins and arches are believed to form slowly over long periods of time by physical and chemical weathering
12.
Stack (geology)
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A stack or sea stack is a geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast, formed by wave erosion. Stacks are formed over time by wind and water, processes of coastal geomorphology and they are formed when part of a headland is eroded by hydraulic action, which is the force of the sea or water crashing against the rock. The force of the water weakens cracks in the headland, causing them to collapse, forming free-standing stacks. Without the constant presence of water, stacks also form when a natural arch collapses under gravity, erosion causes the arch to collapse, leaving the pillar of hard rock standing away from the coast—the stack. Eventually, erosion will cause the stack to collapse, leaving a stump, stacks can provide important nesting locations for seabirds, and many are popular for rock climbing. Isolated steep-sided, rocky islets, typically of volcanic origin, are also loosely called stacks or volcanic stacks. Stacks typically form in horizontally-bedded sedimentary or volcanic rocks, particularly on limestone cliffs and these rock types medium hardness means medium resistance to abrasive and attritive erosion. A more resistant layer may form a capstone, the formation process usually begins when the sea attacks small cracks in a headland and opens them. The cracks then gradually get larger and turn into a small cave, when the cave wears through the headland, an arch forms. Further erosion causes the arch to collapse, leaving the pillar of hard rock standing away from the coast—the stack, eventually, erosion will cause the stack to collapse, leaving a stump. This stump usually forms a rock island, low enough for a high tide to submerge. Some stacks last for a very long time—possibly because they do not get submerged easily, balls Pyramid, the tallest sea stack in the world List of sea stacks
13.
Weathering
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Weathering is the breaking down of rocks, soil, and minerals as well as wood and artificial materials through contact with the Earths atmosphere, waters, and biological organisms. Two important classifications of weathering processes exist – physical and chemical weathering, mechanical or physical weathering involves the breakdown of rocks and soils through direct contact with atmospheric conditions, such as heat, water, ice and pressure. While physical weathering is accentuated in very cold or very dry environments, chemical reactions are most intense where the climate is wet, however, both types of weathering occur together, and each tends to accelerate the other. For example, physical abrasion decreases the size of particles and therefore increases their surface area, the various agents act in concert to convert primary minerals to secondary minerals and release plant nutrient elements in soluble forms. The materials left over after the rock breaks down combined with organic material creates soil, in addition, many of Earths landforms and landscapes are the result of weathering processes combined with erosion and re-deposition. Physical weathering, also recognized as mechanical weathering, is the class of processes that causes the disintegration of rocks without chemical change, the primary process in physical weathering is abrasion. However, chemical and physical weathering often go hand in hand, physical weathering can occur due to temperature, pressure, frost etc. For example, cracks exploited by physical weathering will increase the area exposed to chemical action. Abrasion by water, ice, and wind loaded with sediment can have tremendous cutting power, as is amply demonstrated by the gorges, ravines. In glacial areas, huge moving ice masses embedded with soil and rock fragments grind down rocks in their path, plant roots sometimes enter cracks in rocks and pry them apart, resulting in some disintegration, Burrowing animals may help disintegrate rock through their physical action. However, such influences are usually of importance in producing parent material when compared to the drastic physical effects of water, ice, wind. Physical weathering is called mechanical weathering or disaggregation. Thermal stress weathering results from the expansion and contraction of rock, for example, heating of rocks by sunlight or fires can cause expansion of their constituent minerals. As some minerals expand more than others, temperature changes set up differential stresses that cause the rock to crack apart. Because the outer surface of a rock is often warmer or colder than the more protected inner portions and this process may be sharply accelerated if ice forms in the surface cracks. When water freezes, it expands with a force of about 1465 Mg/m^2, disintegrating huge rock masses, thermal stress weathering comprises two main types, thermal shock and thermal fatigue. Thermal stress weathering is an important mechanism in deserts, where there is a diurnal temperature range, hot in the day. The repeated heating and cooling exerts stress on the layers of rocks
14.
Sandstone
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Sandstone is a clastic sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz or feldspar because these are the most common minerals in the Earths crust, like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, quartz-bearing sandstone is converted into quartzite through heating and pressure, usually related to tectonic compression within orogenic belts. They are formed from cemented grains that may either be fragments of a rock or be mono-minerallic crystals. The cements binding these grains together are typically calcite, clays, grain sizes in sands are defined within the range of 0.0625 mm to 2 mm. The formation of sandstone involves two principal stages, first, a layer or layers of sand accumulates as the result of sedimentation, either from water or from air. Typically, sedimentation occurs by the settling out from suspension. The most common cementing materials are silica and calcium carbonate, which are derived either from dissolution or from alteration of the sand after it was buried. Colours will usually be tan or yellow, a predominant additional colourant in the southwestern United States is iron oxide, which imparts reddish tints ranging from pink to dark red, with additional manganese imparting a purplish hue. Red sandstones are seen in the Southwest and West of Britain, as well as central Europe. The regularity of the latter favours use as a source for masonry, either as a building material or as a facing stone. These physical properties allow the grains to survive multiple recycling events. Quartz grains evolve from rock, which are felsic in origin. Feldspathic framework grains are commonly the second most abundant mineral in sandstones, Feldspar can be divided into two smaller subdivisions, alkali feldspars and plagioclase feldspars. The different types of feldspar can be distinguished under a petrographic microscope, below is a description of the different types of feldspar. Alkali feldspar is a group of minerals in which the composition of the mineral can range from KAlSi3O8 to NaAlSi3O8. Plagioclase feldspar is a group of solid solution minerals that range in composition from NaAlSi3O8 to CaAl2Si2O8. Lithic framework grains are pieces of ancient source rock that have yet to weather away to individual mineral grains, accessory minerals are all other mineral grains in a sandstone, commonly these minerals make up just a small percentage of the grains in a sandstone
15.
Limestone
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Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate, about 10% of sedimentary rocks are limestones. The solubility of limestone in water and weak acid solutions leads to karst landscapes, most cave systems are through limestone bedrock. The first geologist to distinguish limestone from dolomite was Belsazar Hacquet in 1778, like most other sedimentary rocks, most limestone is composed of grains. Most grains in limestone are skeletal fragments of organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids, intraclasts and these organisms secrete shells made of aragonite or calcite, and leave these shells behind when they die. Limestone often contains variable amounts of silica in the form of chert or siliceous skeletal fragment, some limestones do not consist of grains at all, and are formed completely by the chemical precipitation of calcite or aragonite, i. e. travertine. Secondary calcite may be deposited by supersaturated meteoric waters and this produces speleothems, such as stalagmites and stalactites. Another form taken by calcite is oolitic limestone, which can be recognized by its granular appearance, the primary source of the calcite in limestone is most commonly marine organisms. Some of these organisms can construct mounds of rock known as reefs, below about 3,000 meters, water pressure and temperature conditions cause the dissolution of calcite to increase nonlinearly, so limestone typically does not form in deeper waters. Limestones may also form in lacustrine and evaporite depositional environments, calcite can be dissolved or precipitated by groundwater, depending on several factors, including the water temperature, pH, and dissolved ion concentrations. Calcite exhibits a characteristic called retrograde solubility, in which it becomes less soluble in water as the temperature increases. Impurities will cause limestones to exhibit different colors, especially with weathered surfaces, Limestone may be crystalline, clastic, granular, or massive, depending on the method of formation. Crystals of calcite, quartz, dolomite or barite may line small cavities in the rock, when conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together, or it can fill fractures. Travertine is a banded, compact variety of limestone formed along streams, particularly there are waterfalls. Calcium carbonate is deposited where evaporation of the leaves a solution supersaturated with the chemical constituents of calcite. Tufa, a porous or cellular variety of travertine, is found near waterfalls, coquina is a poorly consolidated limestone composed of pieces of coral or shells. During regional metamorphism that occurs during the building process, limestone recrystallizes into marble
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Erosion
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In earth science, erosion is the action of surface processes that remove soil, rock, or dissolved material from one location on the Earths crust, then transport it away to another location. Eroded sediment or solutes may be transported just a few millimetres, the rates at which such processes act control how fast a surface is eroded. Feedbacks are also possible between rates of erosion and the amount of eroded material that is carried by, for example. Processes of erosion that produce sediment or solutes from a place contrast with those of deposition, while erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. At well-known agriculture sites such as the Appalachian Mountains, intensive farming practices have caused erosion up to 100x the speed of the rate of erosion in the region. Excessive erosion causes both on-site and off-site problems, on-site impacts include decreases in agricultural productivity and ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of bodies, as well as sediment-related damage to roads. Intensive agriculture, deforestation, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion, however, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall, and the surface runoff which may result from rainfall, produces four types of soil erosion, splash erosion, sheet erosion, rill erosion. Splash erosion is generally seen as the first and least severe stage in the erosion process. In splash erosion, the impact of a falling raindrop creates a crater in the soil. The distance these soil particles travel can be as much as 0.6 m vertically and 1.5 m horizontally on level ground. If the soil is saturated, or if the rate is greater than the rate at which water can infiltrate into the soil. If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope, sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes, generally, where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are typically of the order of a few centimetres or less and this means that rills exhibit hydraulic physics very different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when water accumulates and rapidly flows in narrow channels during or immediately after heavy rains or melting snow
17.
Geologic time scale
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The table of geologic time spans, presented here, agrees with the nomenclature, dates and standard color codes set forth by the International Commission on Stratigraphy. Evidence from radiometric dating indicates that Earth is about 4.54 billion years old, the geology or deep time of Earth’s past has been organized into various units according to events which took place in each period. Older time spans, which predate the reliable record, are defined by their absolute age. Some other planets and moons within the Solar System have sufficiently rigid structures to have preserved records of their own histories, for example, Venus, Mars, dominantly fluid planets, such as the gas giants, do not preserve their history in a comparable manner. Apart from the Late Heavy Bombardment, events on other planets probably had little influence on the Earth. Construction of a scale that links the planets is, therefore, of only limited relevance to the Earths time scale. The existence, timing, and terrestrial effects of the Late Heavy Bombardment is still debated, the largest defined unit of time is the supereon, composed of eons. Eons are divided into eras, which are in turn divided into periods, epochs, the terms eonothem, erathem, system, series, and stage are used to refer to the layers of rock that correspond to these periods of geologic time in Earths history. Geologists qualify these units as early, mid, and late when referring to time, and lower, middle, for example, the lower Jurassic Series in chronostratigraphy corresponds to the early Jurassic Epoch in geochronology. The adjectives are capitalized when the subdivision is formally recognized, and lower case when not, thus early Miocene but Early Jurassic. Geologic units from the time but different parts of the world often look different and contain different fossils. For example, in North America the Lower Cambrian is called the Waucoban series that is subdivided into zones based on succession of trilobites. In East Asia and Siberia, the unit is split into Alexian, Atdabanian. A key aspect of the work of the International Commission on Stratigraphy is to reconcile this conflicting terminology, the term Anthropocene is used informally by popular culture and a growing number of scientists to describe the current epoch in which we are living. The term was coined by Paul Crutzen and Eugene Stoermer in 2000 to describe the current time, others say that humans have not even started to leave their biggest impact on Earth, and therefore the Anthropocene hasnt even started yet. Whatever the case, the ICS has not officially approved the term, leonardo da Vinci concurred with Aristotles interpretation that fossils represented the remains of ancient life. The 11th-century Persian geologist Avicenna and the 13th-century Dominican bishop Albertus Magnus extended Aristotles explanation into a theory of a petrifying fluid. Avicenna also first proposed one of the principles underlying geologic time scales, the Chinese naturalist Shen Kuo also recognized the concept of deep time
18.
Stratum
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In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers. The stratum is the unit in a stratigraphic column and forms the basis of the study of stratigraphy. Each layer is one of a number of parallel layers that lie one upon another. They may extend over hundreds of thousands of kilometers of the Earths surface. Strata are typically seen as bands of different colored or differently structured material exposed in cliffs, road cuts, quarries, individual bands may vary in thickness from a few millimeters to a kilometer or more. Each band represents a mode of deposition, river silt, beach sand, coal swamp, sand dune, lava bed. Geologists study rock strata and categorize them by the material of beds, each distinct layer is typically assigned to the name of sheet, usually based on a town, river, mountain, or region where the formation is exposed and available for study. For example, the Burgess Shale is an exposure of dark, occasionally fossiliferous. Slight distinctions in material in a formation may be described as members, formations are collected into groups while groups may be collected into supergroups. Archaeological horizon Geologic formation Geologic map Geologic unit Law of superposition Bed GeoWhen Database
19.
Rock shelter
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A rock shelter is a shallow cave-like opening at the base of a bluff or cliff. In arid areas, wind erosion can be an important factor in rockhouse formation, erosion from moving water is seldom a significant factor. Many rock shelters are found under waterfalls, Rock shelter formation types Rock shelters are often important archaeologically. Because rock shelters form natural shelters from the weather, prehistoric humans often used them as living-places, and left behind debris, tools, in mountainous areas the shelters can also be important for mountaineers. In western Connecticut and eastern New York, many shelters are known by the colloquialism leatherman caves. Sandstone can be used as shingles for roof tops when possible, the Cumberland stitchwort is an endangered species of plant which is found only in rock shelters in Kentucky and Tennessee. Gatecliff Rockshelter Kinlock Shelter Mesa Verde Overhang Roc-aux-Sorciers Shelter Rock Walnut Canyon
20.
Caprock
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Caprock or cap rock is a harder or more resistant rock type overlying a weaker or less resistant rock type. Common types of caprock are sandstone and mafic rock types, in processes such as scarp retreat, the caprock controls the rate of erosion of the scarp. As the softer rock is cut away, periodically the caprock shears off, Caprock is also found on the top of mesa formations. The Niagara Escarpment, over which Niagara Falls flows, is an example of a scarp or escarpment, at Niagara Falls, the caprock is the riverbed above the falls, and is what prevents the river from eroding the face of the falls very quickly. In the photo, the thin layer in the foreground where water is not yet running, is the caprock. The Niagara caprock is made of dolomitic limestone, an analogy of caprock could be the outer crust on a cake that is a bit harder than the underlying layer. In the petroleum industry, caprock is any nonpermeable formation that may trap oil, gas or water and this caprock or trap can create a reservoir of oil, gas or water beneath it and is a primary target for the petroleum industry. The tops of salt domes such as in the Gulf of Mexico dissolve in a characteristic manner, the halite is removed first, leaving behind gypsum and anhydrite. The anhydrite and gypsum react with material to form calcite. The classic Murray 1966 paper describes the sequence as sediments-calcite-gypsum-anhydrite-salt. Caprock Escarpment Caprock Canyons State Park and Trailway Monadnock Hoodoo
21.
Azure Window
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The Azure Window, also known as the Dwejra Window, was a 28-metre-tall limestone natural arch on the island of Gozo in Malta. It was located in Dwejra Bay, within the limits of San Lawrenz, close to the Inland Sea and the Fungus Rock, the arch, together with other natural features in the area, has appeared in a number of international films and media productions. The formation was created by the collapse of a sea cave and it consisted of a pillar of rock rising from the sea and joined to the cliff by a horizontal slab. Following decades of natural erosion that caused parts of the arch to fall into the sea, the Azure Window developed through sea and rain erosion of a cliff face, initially as a crack, then a cave and finally an arch. It is not known exactly when the arch came to being, the arch is not mentioned in 17th and 18th century descriptions of the Dwejra area, which was already famous due to the nearby Fungus Rock, so it probably did not exist then. Therefore, it is likely that when the Azure Window formed it inherited its name from this other cave, the earliest known record of the Azure Window is in an 1824 illustration of the nearby Dwejra Tower. However, it is shown in the background of the image, in 1866, artist Edward Lear visited Dwejra and stated in his journal that the coast scenery is not nearly as fine as that of Malta, suggesting that the arch did not exist. The earliest recorded photographs of the arch were probably taken by Richard Ellis. This means that the window might have formed sometime between 1866 and 1879, throughout the 20th and early 21st centuries, the arch was one of Maltas main tourist landmarks, and it was a popular backdrop in photographs. It was included in a Special Area of Conservation, and in 1998, it was included on Maltas tentative list of UNESCO World Heritage Sites, between the 1980s and the 2000s, parts of the top slab of the arch collapsed, significantly widening the arch. A large slab of rock on the edge of the cavity collapsed in April 2012. Another rock fall occurred in March 2013, further rock falls and fissures were reported in subsequent years. Fishermen avoided going near the arch with their boats, and warning signs were put up to people from walking on top. However, many people went on the arch on a regular basis. In March 2016, Dr. Gatt warned that the use of explosives at the nearby Inland Sea could have an effect on the weak structure of the nearby Azure Window. It was suspected that the cutting was aimed at widening the entrance to allow larger boats to sail through. In December 2016, an order was published prohibiting people from going on the arch. However, this law was not enforced, and visitors were still walking on top of the days before it collapsed in March 2017
22.
Malta
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Malta, officially known as the Republic of Malta, is a Southern European island country consisting of an archipelago in the Mediterranean Sea. It lies 80 km south of Italy,284 km east of Tunisia, the country covers just over 316 km2, with a population of just under 450,000, making it one of the worlds smallest and most densely populated countries. The capital of Malta is Valletta, which at 0.8 km2, is the smallest national capital in the European Union, Malta has one national language, which is Maltese, and English as an official language. John, French and British, have ruled the islands, King George VI of the United Kingdom awarded the George Cross to Malta in 1942 for the countrys bravery in the Second World War. The George Cross continues to appear on Maltas national flag, the country became a republic in 1974, and although no longer a Commonwealth realm, remains a member state of the Commonwealth of Nations. Malta was admitted to the United Nations in 1964 and to the European Union in 2004, in 2008, Catholicism is the official religion in Malta. The origin of the term Malta is uncertain, and the modern-day variation derives from the Maltese language, the most common etymology is that the word Malta derives from the Greek word μέλι, meli, honey. The ancient Greeks called the island Μελίτη meaning honey-sweet, possibly due to Maltas unique production of honey, an endemic species of bee lives on the island. The Romans went on to call the island Melita, which can be considered either as a latinisation of the Greek Μελίτη or the adaptation of the Doric Greek pronunciation of the same word Μελίτα. Another conjecture suggests that the word Malta comes from the Phoenician word Maleth a haven or port in reference to Maltas many bays, few other etymological mentions appear in classical literature, with the term Malta appearing in its present form in the Antonine Itinerary. The extinction of the hippos and dwarf elephants has been linked to the earliest arrival of humans on Malta. Prehistoric farming settlements dating to the Early Neolithic period were discovered in areas and also in caves. The Sicani were the tribe known to have inhabited the island at this time and are generally regarded as being closely related to the Iberians. Pottery from the Għar Dalam phase is similar to found in Agrigento. A culture of megalithis temple builders then either supplanted or arose from this early period, the temples have distinctive architecture, typically a complex trefoil design, and were used from 4000 to 2500 BCE. Animal bones and a knife found behind an altar stone suggest that temple rituals included animal sacrifice. Tentative information suggests that the sacrifices were made to the goddess of fertility, the culture apparently disappeared from the Maltese Islands around 2500 BC. Archaeologists speculate that the builders fell victim to famine or disease
23.
Discordant coastline
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A discordant coastline occurs where bands of different rock type run perpendicular to the coast. The differing resistance to erosion leads to the formation of headlands, a hard rock type such as granite is resistant to erosion and creates a promontory whilst a softer rock type such as the clays of Bagshot Beds is easily eroded creating a bay. Part of the Dorset coastline running north from the Portland limestone of Durlston Head is an example of a discordant coastline. The Portland limestone is resistant to erosion, then to the north there is a bay at Swanage where the type is a softer greensand. North of Swanage, the chalk outcrop creates the headland which includes Old Harry Rocks, the converse of a discordant coastline is a concordant coastline. The coastline around Swanage is an example of a discordant coastline
24.
Wave
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In physics, a wave is an oscillation accompanied by a transfer of energy that travels through a medium. Frequency refers to the addition of time, wave motion transfers energy from one point to another, which displace particles of the transmission medium–that is, with little or no associated mass transport. Waves consist, instead, of oscillations or vibrations, around almost fixed locations, there are two main types of waves. Mechanical waves propagate through a medium, and the substance of this medium is deformed, restoring forces then reverse the deformation. For example, sound waves propagate via air molecules colliding with their neighbors, when the molecules collide, they also bounce away from each other. This keeps the molecules from continuing to travel in the direction of the wave, the second main type, electromagnetic waves, do not require a medium. Instead, they consist of periodic oscillations of electrical and magnetic fields generated by charged particles. These types vary in wavelength, and include radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, waves are described by a wave equation which sets out how the disturbance proceeds over time. The mathematical form of this varies depending on the type of wave. Further, the behavior of particles in quantum mechanics are described by waves, in addition, gravitational waves also travel through space, which are a result of a vibration or movement in gravitational fields. While mechanical waves can be transverse and longitudinal, all electromagnetic waves are transverse in free space. A single, all-encompassing definition for the wave is not straightforward. A vibration can be defined as a back-and-forth motion around a reference value, however, a vibration is not necessarily a wave. An attempt to define the necessary and sufficient characteristics that qualify a phenomenon as a results in a blurred line. The term wave is often understood as referring to a transport of spatial disturbances that are generally not accompanied by a motion of the medium occupying this space as a whole. In a wave, the energy of a vibration is moving away from the source in the form of a disturbance within the surrounding medium and it may appear that the description of waves is closely related to their physical origin for each specific instance of a wave process. For example, acoustics is distinguished from optics in that sound waves are related to a rather than an electromagnetic wave transfer caused by vibration. Concepts such as mass, momentum, inertia, or elasticity and this difference in origin introduces certain wave characteristics particular to the properties of the medium involved
25.
Cave
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A cave is a hollow place in the ground, specifically a natural underground space large enough for a human to enter. Caves form naturally by the weathering of rock and often extend deep underground, the word cave can also refer to much smaller openings such as sea caves, rock shelters, and grottos. A cavern is a type of cave, naturally formed in soluble rock with the ability to grow speleothems. Speleology is the science of exploration and study of all aspects of caves, visiting or exploring caves for recreation may be called caving, potholing, or spelunking. The formation and development of caves is known as speleogenesis, which can occur over the course of millions of years, caves are formed by various geologic processes and can be variable sizes. These may involve a combination of processes, erosion from water, tectonic forces, microorganisms, pressure. Isotopic dating techniques can be applied to cave sediments, in order to determine the timescale when geologic events may have occurred to help form and it is estimated that the maximum depth of a cave cannot be more than 3,000 metres due to the pressure of overlying rocks. For karst caves the maximum depth is determined on the basis of the limit of karst forming processes. Most caves are formed in limestone by dissolution, solutional caves or karst caves are the most frequently occurring caves and such caves form in rock that is soluble. Most occur in limestone, but they can form in other rocks including chalk, dolomite, marble, salt. Rock is dissolved by acid in groundwater that seeps through bedding planes, faults, joints. Over geological epochs cracks expand to become caves and cave systems, the largest and most abundant solutional caves are located in limestone. Limestone dissolves under the action of rainwater and groundwater charged with H2CO3, the dissolution process produces a distinctive landform known as karst, characterized by sinkholes and underground drainage. Limestone caves are often adorned with calcium carbonate formations produced through slow precipitation and these include flowstones, stalactites, stalagmites, helictites, soda straws and columns. These secondary mineral deposits in caves are called speleothems, the portions of a solutional cave that are below the water table or the local level of the groundwater will be flooded. Lechuguilla Cave in New Mexico and nearby Carlsbad Cavern are now believed to be examples of type of solutional cave. They were formed by H2S gas rising from below, where reservoirs of oil give off sulfurous fumes and this gas mixes with ground water and forms H2SO4. The acid then dissolves the limestone from below, rather than from above, caves formed at the same time as the surrounding rock are called primary caves
26.
London Arch
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London Arch is an offshore natural arch formation in the Port Campbell National Park, Australia. The arch is a significant tourist attraction along the Great Ocean Road near Port Campbell in Victoria and this stack was formed by a gradual process of erosion, and until 1990 formed a complete double-span natural bridge. The span closer to the shoreline collapsed unexpectedly on 15 January 1990, no one was injured in the event. Prior to the collapse, the arch was known as London Bridge because of its similarity to its namesake, on the website of Geoscience Australia
27.
Victoria (Australia)
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Victoria is a state in southeast Australia. Victoria is Australias most densely populated state and its second-most populous state overall, most of its population is concentrated in the area surrounding Port Phillip Bay, which includes the metropolitan area of its state capital and largest city, Melbourne, Australias second-largest city. Prior to British European settlement, the area now constituting Victoria was inhabited by a number of Aboriginal peoples. With Great Britain having claimed the entire Australian continent east of the 135th meridian east in 1788, Victoria was included in the wider colony of New South Wales. The first settlement in the area occurred in 1803 at Sullivan Bay, and much of what is now Victoria was included in the Port Phillip District in 1836, Victoria was officially created as a separate colony in 1851, and achieved self-government in 1855. Politically, Victoria has 37 seats in the Australian House of Representatives and 12 seats in the Australian Senate, at state level, the Parliament of Victoria consists of the Legislative Assembly and the Legislative Council. Victoria is currently governed by the Labor Party, with Daniel Andrews the current Premier, the personal representative of the Queen of Australia in the state is the Governor of Victoria, currently Linda Dessau. Local government is concentrated in 79 municipal districts, including 33 cities, although a number of unincorporated areas still exist, Victorias total gross state product is ranked second in Australia, although Victoria is ranked fourth in terms of GSP per capita because of its limited mining activity. Culturally, Melbourne is home to a number of museums, art galleries and theatres and is described as the sporting capital of Australia. The Melbourne Cricket Ground is the largest stadium in Australia, and the host of the 1956 Summer Olympics, Victoria has eight public universities, with the oldest, the University of Melbourne, having been founded in 1853. Victoria, like Queensland, was named after Queen Victoria, who had been on the British throne for 14 years when the colony was established in 1851. The first British settlement in the later known as Victoria was established in October 1803 under Lieutenant-Governor David Collins at Sullivan Bay on Port Phillip. In the year 1826 Colonel Stewart, Captain S. Wright, fly and the brigs Dragon and Amity, took a number of convicts and a small force composed of detachments of the 3rd and 93rd regiments. Victorias next settlement was at Portland, on the south west coast of what is now Victoria, edward Henty settled Portland Bay in 1834. Melbourne was founded in 1835 by John Batman, who set up a base in Indented Head, from settlement the region around Melbourne was known as the Port Phillip District, a separately administered part of New South Wales. Shortly after the now known as Geelong was surveyed by Assistant Surveyor W. H. Smythe. And in 1838 Geelong was officially declared a town, despite earlier white settlements dating back to 1826, days later, still in 1851 gold was discovered near Ballarat, and subsequently at Bendigo. Later discoveries occurred at sites across Victoria
28.
Neil Island
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Neill Island is an island of the Andaman Islands, located in Ritchies Archipelago. It belongs to the South Andaman administrative district, part of the Indian union territory of Andaman, the island is lying 36 km northeast from Port Blair. Neill is named after British Brigadier general James Neill, who had dealt with the rebels during the suppression of the 1857 Mutiny. Neill Island was uninhabited until the arrival of settlers in the late 1960s, like Havelock, the vast majority of settlers at Neill were refugees from erstwhile Bangladesh, following the exodus of Hindu Bangladeshis prior to that countrys war of independence in 1971. The island belongs to the Ritchies Archipelago and is located between Havelock Island and Rose Island and it is a comparatively flat island, and much of the landmass was deemed suitable for paddy cultivation. Unfortunately, as a result of this, very little forest cover remains at Neil, Neill island tends to remain a degree or two warmer than Havelock as a result of the lack of forest cover. The island is not without charm however, but it is a different, politically, Neill Island is part of Neill Kendra panchayat, of Port Blair Taluk. There are regular Government ferry from Port Blair to Neill Island, there are private cruise ships such as Makruzz and Coastal Cruise. Agriculture is the occupation of the villagers, and the island supplies vegetables to the rest of Andaman. Despite its minuscule tourist infrastructure, a number of tourists have chosen to stay at Neill Island instead of neighboring Havelock Island. There are a handful of restaurants and basic beach hotels that cater to international and domestic tourists
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Andaman Islands
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The Andaman Islands form an archipelago in the Bay of Bengal between India, to the west, and Myanmar, to the north and east. Most are part of the Andaman and Nicobar Islands Union Territory of India, while a number in the north of the archipelago, including the Coco Islands. The Andaman Islands are home to the Sentinelese, who have had no contact with any other people, the name of the Andaman Islands is ancient. A theory that became prevalent in the late 19th century is that it derives from Andoman, a form of Hanuman, another Italian traveller, Niccolò de Conti, mentioned the islands and said that the name means Island of Gold. The Andaman islands have been inhabited for several years, at the very least. The indigenous Andamanese people appear to have lived on the islands in substantial isolation from that time until the 18th century CE, from 800 to 1200 CE, the Tamil Chola dynasty created an empire that eventually extended from southeastern peninsular India to parts of Malaysia. Rajendra Chola I took over the Andaman and Nicobar Islands and maintained them as a naval base to launch a naval expedition against the Srivijaya empire. In 1789, Bengal Presidency established a base and penal colony on Chatham Island in the southeast bay of Great Andaman. The settlement is now known as Port Blair, after two years, the colony was moved to the northeast part of Great Andaman and was named Port Cornwallis after Admiral William Cornwallis. However, there was disease and death in the penal colony. In 1824, Port Cornwallis was the rendezvous of the carrying the army to the First Burmese War. In the 1830s and 1840s, shipwrecked crews who landed on the Andamans were often attacked and killed by the natives, in 1855, the government proposed another settlement on the islands, including a convict establishment, but the Indian Rebellion of 1857 forced a delay in its construction. However, because the rebellion gave the British so many prisoners, it made the new Andaman settlement and prison urgently necessary. Construction began in November 1857 at Port Blair using inmates labour,17 May 1859 was another major day for Andaman. The Battle of Aberdeen was fought between the Great Andamanese Tribe and the British, today, a memorial stands in Andaman Water sports complex as a tribute to the people who lost their life. Fearing foreign invasion and with help from a convict from Cellular Jail, the great Andamanese tribe stormed the British post. Later, it was identified that a convict named Doodnath had changed sides. Today, the tribe has been reduced to some 50 people, the government of Andaman Islands is making efforts to increase the headcount of this tribe
30.
Concordant coastline
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A concordant, longitudinal, or Pacific type coastline occurs where beds, or layers, of differing rock types are folded into ridges that run parallel to the coast. The outer hard rock provides a barrier to erosion of the softer rocks further inland. Sometimes the outer hard rock is punctured, allowing the sea to erode the softer rocks behind and this creates a cove, a circular area of water with a relatively narrow entrance from the sea. Lulworth Cove in Dorset is situated on a concordant coastline, the outer hard rock is Portland limestone. The sea has broken through this barrier and easily eroded the clays behind it, a chalk cliff face at the back of the cove slows further erosion. Erosion is just starting to the west, where the sea has broken through the Portland limestone barrier at Stair Hole. The concordant coast may take one of two landform types, the Dalmatian type, named from Dalmatia on the Adriatic Sea, features long offshore islands and coastal inlets that are parallel to the coastline. The Adriatic Sea itself is a concordant landform, consisting of a body of water between parallel ranges. The second landform is the Haff type as in the Haffs, or lagoons, of the shore of the Baltic Sea. The converse of concordant coastline is a discordant coastline
31.
Shale
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Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable, shale is characterized by breaks along thin laminae or parallel layering or bedding less than one centimeter in thickness, called fissility. Mudstones, on the hand, are similar in composition. Before the mid 19th century, the slate, shale. In the context of underground mining, shale was frequently referred to as slate well into the 20th century. Non-fissile rocks of similar composition but made of smaller than 0.06 mm are described as mudstones or claystone. Rocks with similar sizes but with less clay and therefore grittier are siltstones. Shale is the most common sedimentary rock, shales are typically composed of variable amounts of clay minerals and quartz grains and the typical color is gray. Addition of variable amounts of minor constituents alters the color of the rock, black shale results from the presence of greater than one percent carbonaceous material and indicates a reducing environment. Black shale can also be referred to as black metal, red, brown and green colors are indicative of ferric oxide, iron hydroxide, or micaceous minerals. Clays are the constituent of shales and other mudrocks. The clay minerals represented are largely kaolinite, montmorillonite and illite, clay minerals of Late Tertiary mudstones are expandable smectites whereas in older rocks especially in mid- to early Paleozoic shales illites predominate. The transformation of smectite to illite produces silica, sodium, calcium, magnesium, iron and these released elements form authigenic quartz, chert, calcite, dolomite, ankerite, hematite and albite, all trace to minor minerals found in shales and other mudrocks. Shales and mudrocks contain roughly 95 percent of the matter in all sedimentary rocks. However, this amounts to less than one percent by mass in an average shale, black shales, which form in anoxic conditions, contain reduced free carbon along with ferrous iron and sulfur. Pyrite and amorphous iron sulfide along with carbon produce the black coloration, the process in the rock cycle which forms shale is called compaction. The fine particles that compose shale can remain suspended in long after the larger particles of sand have deposited. Shales are typically deposited in very slow moving water and are found in lakes and lagoonal deposits, in river deltas, on floodplains
32.
Durdle Door
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Durdle Door is a natural limestone arch on the Jurassic Coast near Lulworth in Dorset, England. It is privately owned by the Welds, a family who owns 12,000 acres in Dorset in the name of the Lulworth Estate and it is open to the public. The name Durdle is derived from the Old English thirl meaning bore or drill, the form of the coastline around Durdle Door is controlled by its geology—both by the contrasting hardnesses of the rocks, and by the local patterns of faults and folds. The arch has formed on a concordant coastline where bands of rock run parallel to the shoreline, the rock strata are almost vertical, and the bands of rock are quite narrow. Originally a band of resistant Portland limestone ran along the shore, behind this is a 120-metre band of weaker, easily eroded rocks, and behind this is a stronger and much thicker band of chalk, which forms the Purbeck Hills. These steeply dipping rocks are part of the structure known as the Lulworth crumple. The limestone and chalk are in proximity at Durdle Door than at Swanage,10 miles to the east. Around this part of the coast nearly all of the limestone has been removed by sea erosion, erosion at the western end of the limestone band has resulted in the arch formation. UNESCO teams monitor the condition of both the arch and adjacent beach. In Man O War Bay, the bay immediately east of Durdle Door, the band of Portland and Purbeck limestone has not been entirely eroded away. Similarly, offshore to the west, the limestone outcrop forms a line of small rocky islets called The Bull, The Blind Cow, The Cow. There is a dearth of written records about the arch. In the late eighteenth century there is a description of the magnificent arch of Durdle-rock Door, in 1811 the first Ordnance Survey map of the area named it as Dirdale Door. Durdle is derived from the Old English thirl, meaning to pierce, bore or drill, the Geology of the Country around Weymouth, Swanage, Corfe and Lulworth, 4th pr. London, Geological Survey of Great Britain, HMSO, a Geological Guide to the Dorset Coast, 2nd ed. London, Adam & Charles Black
33.
Lulworth Cove
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Lulworth Cove is a cove near the village of West Lulworth, on the Jurassic Coast World Heritage Site in Dorset, southern England. The cove is one of the worlds finest examples of such a landform and it is close to the rock arch of Durdle Door and other Jurassic Coast sites. Lulworth Cove featured on the TV programme Seven Natural Wonders as one of the wonders of southern England, the cove has formed as a result of bands of rock of alternating resistance running parallel to the shore. On the seaward side the clays and sands have been eroded away, a narrow band of Portland limestone rocks forms the shoreline. Behind this is a band of slightly less resistant Purbeck limestone. Behind this are 300–350 metres of much less resistant clays and greensands, forming the back of the cove is a 250-metre-wide band of chalk, which is considerably more resistant than the clays and sands, but less resistant than the limestones. The entrance to the cove is a gap in the limestone bands, formed by wave action. The wide part of the cove is where the weak clays, at the back of the cove, the sea has been unable to erode the chalk as fast because chalk does not dissolve in the sea acids. The unique shape of the cove is a result of wave diffraction, the narrow entrance to the cove causes waves to bend into an arced shape, as is visible in the photograph below. Stair Hole, less than half a mile away, is an infant cove which suggests what Lulworth Cove would have looked like a few hundred years ago. The sea has made a gap in the Portland and Purbeck limestone here, the sea has made its way through to the Wealdon clays and begun eroding them. The clay shows obvious signs of slumping, and is eroding very rapidly, stair Hole shows one of the best examples of limestone folding in the world, caused by movements in the Earths crust millions of years ago. Folding can also be seen at nearby Durdle Door and at Lulworth cove itself, Lulworth acts as a gateway to this part of the Jurassic Coast. As well as the cove, across Hambury Tout is Durdle Door, to the east there is a fossilised forest. Lulworth is also close to Kimmeridge, famous for its rocky shore, oil-bearing sands beneath the sea bed form the largest British oil field outside the North Sea area, and contain the highest quality oil in Europe. Geologists and geographers have been interested in the area since the beginning of the 19th century, since then the area has drawn Geology students from all over the world. Purbeck suffers from trampling because of its visitors and erosion from the sea. Management has been put in place to stop the coastline from being ruined, such as wooden steps and these will keep people to a certain path and steps will reinforce the ground
34.
Dorset
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Dorset /ˈdɔːrsᵻt/ is a county in South West England on the English Channel coast. The ceremonial county comprises the county, which is governed by Dorset County Council. Covering an area of 2,653 square kilometres, Dorset borders Devon to the west, Somerset to the north-west, Wiltshire to the north-east, the county town is Dorchester which is in the south. After the reorganisation of government in 1974 the countys border was extended eastward to incorporate the Hampshire towns of Bournemouth. Around half of the lives in the South East Dorset conurbation. The county has a history of human settlement stretching back to the Neolithic era. The Romans conquered Dorsets indigenous Celtic tribe, and during the early Middle Ages, the first recorded Viking raid on the British Isles occurred in Dorset during the eighth century, and the Black Death entered England at Melcombe Regis in 1348. During the Second World War, Dorset was heavily involved in the preparations for the invasion of Normandy, the former was the sailing venue in the 2012 Summer Olympics, and both have clubs or hire venues for sailing, Cornish pilot gig rowing, sea kayaking and powerboating. Dorset has a varied landscape featuring broad elevated chalk downs, steep limestone ridges, over half the county is designated as an Area of Outstanding Natural Beauty. Three-quarters of its coastline is part of the Jurassic Coast Natural World Heritage Site due to its geological and it features notable landforms such as Lulworth Cove, the Isle of Portland, Chesil Beach and Durdle Door. Agriculture was traditionally the major industry of Dorset but is now in decline, there are no motorways in Dorset but a network of A roads cross the county and two railway main lines connect to London. Dorset has ports at Poole, Weymouth and Portland, and an international airport, the county has a variety of museums, theatres and festivals, and is host to one of Europes largest outdoor shows. It is the birthplace of Thomas Hardy, who used the county as the setting of his novels. Dorset derives its name from the county town of Dorchester, the Romans established the settlement in the 1st century and named it Durnovaria which was a Latinised version of a Common Brittonic word possibly meaning place with fist-sized pebbles. It is first mentioned in the Anglo-Saxon Chronicle in AD845 and in the 10th century the countys archaic name, the first human visitors to Dorset were Mesolithic hunters, from around 8000 BC. The first permanent Neolithic settlers appeared around 3000 BC and were responsible for the creation of the Dorset Cursus, from 2800 BC onwards Bronze Age farmers cleared Dorsets woodlands for agricultural use and Dorsets high chalk hills provided a location for numerous round barrows. During the Iron Age, the British tribe known as the Durotriges established a series of forts across the county—most notably Maiden Castle which is one of the largest in Europe. The Romans arrived in Dorset during their conquest of Britain in AD43, Maiden Castle was captured by a Roman legion under the command of Vespasian, and the Roman settlement of Durnovaria was established nearby
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Jurassic Coast
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The Jurassic Coast is a World Heritage Site on the English Channel coast of southern England. It stretches from Exmouth in East Devon to Studland Bay in Dorset, a distance of about 96 mi, the site spans 185 million years of geological history, coastal erosion having exposed an almost continuous sequence of rock formation covering the Triassic, Jurassic and Cretaceous periods. At different times, this area has been desert, shallow sea and marsh. Natural features seen on this stretch of coast include arches, pinnacles, in some places the sea has broken through resistant rocks to produce coves with restricted entrances, and in one place, the Isle of Portland is connected to the land by a narrow spit. In some parts of the coast, landslides are common and these have exposed a wide range of fossils, the different rock types each having its own typical fauna and flora, thus providing evidence of how animals and plants evolved in this region. The area around Lulworth Cove contains a fossil forest, and 71 different rock strata have been identified at Lyme Regis, each with its own species of ammonite. The fossil collector Mary Anning lived here and her discoveries of marine reptiles. The Charmouth Heritage Coast Centre provides information on the heritage coast, the Jurassic Coast stretches from Orcombe Point near Exmouth in East Devon to Old Harry Rocks near Swanage in East Dorset, a distance of 96 mi. Inscribed on the World Heritage List in 2001, the Jurassic Coast was the first wholly natural World Heritage Site to be designated in the United Kingdom. At Orcombe Point, the Geoneedle, an acute pyramidal sculpture, marks the end of the heritage site. The cliffs on part of the coast are being eroded as sections crumble away. The fossils found in the area and the coastal features of this dynamic coast, have advanced the study of earth sciences for more than two hundred years. The area covered by the designation comprises the land between the low water mark and the top of the cliffs or the back of the beach. The fossils found in abundance along this coastline provide evidence of how animals, during the Triassic this area was a desert, while in the Jurassic it was part of a tropical sea, and in the Cretaceous it was covered by swamps. Fossil groups found here include crustaceans, insects, molluscs, echinoderms, fish, amphibians, reptiles, at Lulworth Cove there is a fossil forest of conifers, tree-ferns and cycads. The Jurassic Coast consists of Triassic, Jurassic and Cretaceous cliffs, spanning the Mesozoic, documenting 185 million years of geological history. The site can be best viewed from the sea, when the nature of the rock strata becomes apparent. Further east at Ladram Bay. Around Lyme Regis and Charmouth the cliffs are of Jurassic clays and shale, chesil Beach is a good example of a barrier beach and stretches for 18 mi from Burton Bradstock to the Isle of Portland
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Cove
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A cove is a small type of bay or coastal inlet. Coves usually have narrow, restricted entrances, are circular or oval. Small, narrow, sheltered bays, inlets, creeks, or recesses in a coast are often considered coves, colloquially, the term can be used to describe a sheltered bay. Geomorphology describes coves as precipitously-walled and rounded cirque-like openings as in a valley extending into or down a mountainside, coves are formed by differential erosion, which occurs when softer rocks are worn away faster than the harder rocks surrounding them. These rocks further erode to form a bay with a narrow entrance. A notable example is Lulworth Cove on the Jurassic Coast in Dorset, to its west, a second cove, Stair Hole, is forming. Clark, John O. E. Stiegler, Stella, the Facts on File, Dictionary of Earth Science. New York, Market House Books Ltd
37.
Canyonlands National Park
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Canyonlands National Park is a U. S. National Park located in southeastern Utah near the town of Moab. It preserves a colorful landscape eroded into countless canyons, mesas, and buttes by the Colorado River, the Green River, legislation creating the park was signed into law by President Lyndon Johnson on September 12,1964. The park is divided into four districts, the Island in the Sky, the Needles, the Maze, while these areas share a primitive desert atmosphere, each retains its own character. Author Edward Abbey, a frequent visitor, described the Canyonlands as the most weird, wonderful, Canyonlands is a popular recreational destination. Since 2007, more than 400,000 people have visited the park each year with a record of 776,218 visitors in 2016, the geography of the park is well suited to a number of different recreational uses. Hikers, mountain bikers, backpackers, and four-wheelers all enjoy traveling the rugged, the White Rim Road traverses the White Rim Sandstone level of the park between the rivers and the Island in the Sky. Since 2015, day-use permits must be obtained before travelling on the White Rim Road due to the popularity of driving and bicycling along it. The park services intent is to provide a wilderness experience for all visitors while minimizing impacts on the natural surroundings. Rafters and kayakers float the calm stretches of the Green River, below the Confluence, Cataract Canyon contains powerful whitewater rapids, similar to those found in the Grand Canyon. However, since there is no large impoundment on the Colorado River above Canyonlands National Park, river flow through the Confluence is determined by snowmelt, not management. As a result, and in combination with Cataract Canyons unique graben geology, as of 2016, the Island in the Sky district, with its proximity to the Moab, Utah area, attracts 76.7 percent of total park visitors. The Needles district is the second most visited, drawing 20.7 percent of visitors, the remote Maze district accounts for only about 1.5 percent of visitors, while river rafters and other river users account for the remaining 1.1 percent of total park visitation. Political compromise at the time of the parks creation limited the area to an arbitrary portion of the Canyonlands basin. Conservationists hope to complete the park by bringing the boundaries up to the high sandstone rims that form the border of the Canyonlands landscape. The Colorado River and Green River combine within the park dividing it into three districts called the Island in the Sky, the Needles and the Maze, the Colorado River flows through Cataract Canyon below its confluence with the Green River. The area was home of the Ancestral Puebloans, of which many traces can be found. Although the items and tools used have been largely taken away by looters, some of their stone. The Ancestral Puebloans also left traces in the form of petroglyphs, the Maze district is located west of the Colorado and Green rivers, and is the least accessible section of the park, and one of the most remote and inaccessible areas of the United States
38.
Grand Staircase-Escalante National Monument
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The Grand Staircase-Escalante National Monument is a U. S. National Monument protecting 1,880,461 acres of land in southern Utah. President Bill Clinton designated the area as a monument in 1996 using his authority under the Antiquities Act. Grand Staircase-Escalante encompasses the largest land area of all U. S. National Monuments, the Monument is managed by the Bureau of Land Management rather than the National Park Service. This was the first National Monument managed by the BLM, visitor centers are located in Cannonville, Big Water, Escalante, and Kanab. The Monument stretches from the towns of Big Water, Glendale and Kanab, Utah on the southwest, to the towns of Escalante, encompassing 1.9 million acres, the Monument is slightly larger in area than the state of Delaware. The western part of the Monument is dominated by the Paunsaugunt Plateau and the Paria River and this section shows the geologic progression of the Grand Staircase. Features include the slot canyons of Bull Valley Gorge, Willis Creek, the center section is dominated by a single long ridge, called Kaiparowits Plateau from the west, and called Fifty-Mile Mountain when viewed from the east. Fifty-Mile Mountain stretches southeast from the town of Escalante to the Colorado River in Glen Canyon, the eastern face of the mountain is a steep,2200 foot escarpment. The western side is a slope descending to the south. East of Fifty-Mile Mountain are the Canyons of the Escalante, the Monument is bounded by Glen Canyon National Recreation Area on the east and south. The popular hiking, backpacking and canyoneering areas include the slot canyons of Peekaboo, Spooky and Brimstone Canyons, the Devils Garden is also located in this area. Access is via the Hole-in-the-Rock Road which extends southeast from the town of Escalante, the road was constructed to facilitate Mormon settlement of southeastern Utah, including the town of Bluff. The road is used by ranchers to access the flat desert at the base of Fifty Mile Mountain for grazing cattle. Since 2000, numerous fossils over 75 million years old have been found at Grand Staircase-Escalante. In 2002, a volunteer at the Monument discovered a 75-million-year-old dinosaur near the Arizona border, on October 3,2007, the dinosaurs name, Gryposaurus monumentensis was announced in the Zoological Journal of the Linnean Society. G. monumentensis was at least 30 feet long and 10 feet tall, many of the specimens from the Kaiparowits Formation are reposited at the Natural History Museum of Utah in Salt Lake City. Two ceratopsid dinosaurs, also discovered at the Monument, were introduced by the Utah Geological Survey in 2007 and they were uncovered in the Wahweap formation, which is just below the Kaiparowits formation where the duckbill was extracted. They lived about 80 million or 81 million years ago, the two fossils are called the Last Chance skull and the Nipple Butte skull
39.
Topographic map
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Traditional definitions require a topographic map to show both natural and man-made features. A topographic map is published as a map series, made up of two or more map sheets that combine to form the whole map. A contour line is a line connecting places of equal elevation, however, in the vernacular and day to day world, the representation of relief is popularly held to define the genre, such that even small-scale maps showing relief are commonly called topographic. The study or discipline of topography is a broader field of study. Topographic maps are based on topographical surveys, performed at large scales, these surveys are called topographical in the old sense of topography, showing a variety of elevations and landforms. This is in contrast to older cadastral surveys, which primarily show property, the first multi-sheet topographic map series of an entire country, the Carte géométrique de la France, was completed in 1789. Topographic surveys were prepared by the military to assist in planning for battle, as such, elevation information was of vital importance. As they evolved, topographic map series became a resource in modern nations in planning infrastructure. Excluding borders, each sheet was 44 cm high and up to 66 cm wide, although the project eventually foundered, it left an indexing system that remains in use. TIGER was developed in the 1980s and used in the 1990, digital elevation models were also compiled, initially from topographic maps and stereographic interpretation of aerial photographs and then from satellite photography and radar data. Since all these were government projects funded with taxes and not classified for security reasons. Initial applications were mostly professionalized forms such as innovative surveying instruments, by the mid-1990s, increasingly user-friendly resources such as online mapping in two and three dimensions, integration of GPS with mobile phones and automotive navigation systems appeared. As of 2011, the future of standardized, centrally printed topographical maps is left somewhat in doubt, the various features shown on the map are represented by conventional signs or symbols. For example, colors can be used to indicate a classification of roads and these signs are usually explained in the margin of the map, or on a separately published characteristic sheet. Topographic maps are commonly called contour maps or topo maps. In the United States, where the national series is organized by a strict 7. 5-minute grid. Topographic maps conventionally show topography, or land contours, by means of contour lines, contour lines are curves that connect contiguous points of the same altitude. In other words, every point on the line of 100 m elevation is 100 m above mean sea level
40.
Meander
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A meander, in general, is a bend in a sinuous watercourse or river. A meander forms when moving water in a stream erodes the outer banks and widens its valley, a stream of any volume may assume a meandering course, alternately eroding sediments from the outside of a bend and depositing them on the inside. The result is a pattern as the stream meanders back. When a meander gets cut off from the stream, an oxbow lake forms. Over time meanders migrate downstream, sometimes in such a time as to create civil engineering problems for local municipalities attempting to maintain stable roads. There is not yet full consistency or standardization of scientific terminology used to describe watercourses, a variety of symbols and schemes exist. Parameters based on mathematical formulae or numerical data vary as well, unless otherwise defined in a specific scheme meandering and sinuosity here are synonymous and mean any repetitious pattern of bends, or waveforms. In some schemes, meandering applies only to rivers with exaggerated circular loops or secondary meanders, sinuosity is one of the channel types that a stream may assume over all or part of its course. All streams are sinuous at some time in their history over some part of their length. The term derives from the Meander River located in present-day Turkey and known to the Ancient Greeks as Μαίανδρος Maiandros and its course is so exceedingly winding that everything winding is called meandering. The Meander River is located south of Izmir, east of the ancient Greek town of Miletus, now, Milet and it flows through a graben in the Menderes Massif, but has a flood plain much wider than the meander zone in its lower reach. Its modern Turkish name is the Büyük Menderes River, when a fluid is introduced to an initially straight channel which then bends, the sidewalls induce a pressure gradient that causes the fluid to alter course and follow the bend. From here, two opposing processes occur, irrotational flow and secondary flow, for a river to meander, secondary flow must dominate. Irrotational flow, From Bernoullis equations, high pressure results in low velocity, therefore, in the absence of secondary flow we would expect low fluid velocity at the outside bend and high fluid velocity at the inside bend. This classic fluid mechanics result is irrotational vortex flow, in the context of meandering rivers, its effects are dominated by those of secondary flow. Secondary flow, A force balance exists between pressure forces pointing to the bend of the river and centrifugal forces pointing to the outside bend of the river. In the context of meandering rivers, a boundary layer exists within the layer of fluid that interacts with the river bed. Inside that layer and following standard boundary-layer theory, the velocity of the fluid is effectively zero, centrifugal force, which depends on velocity, is also therefore effectively zero
41.
Coyote Gulch
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Coyote Gulch is a tributary of the Escalante River, located in Garfield and Kane Counties in southern Utah, in the western United States. The upper sections of Coyote Gulch are located within the Grand Staircase-Escalante National Monument while its lower sections are located in the Glen Canyon National Recreation Area. The headwaters of Coyote Gulch have their origins along a 14 mi segment of the Straight Cliffs Formation which is the edge of the Kaiparowits Plateau. Intermittent streams flowing down the Straight Cliffs merge to form larger branches, including Dry Fork, Big Hollow, the branch of Coyote Gulch. The combined flow from these branches have carved a canyon up to 900 ft deep into sandstone layers, the main canyon of Coyote Gulch can be accessed by one of several trailheads located along the Hole-in-the-Rock Road. The HITRR is a road that heads southeast into the Grand Staircase-Escalante National Monument. The Red Well trailhead is at the end of a spur road off the HITRR. The trail into Hurricane Wash starts just off the HITRR, a trailhead located near some stock watering tanks along Fortymile Ridge Road—another spur of the HITRR—can be used for a cross-country route to the middle of Coyote Gulch. This route involves a steep climb over slickrock. A trailhead at the end the Fortymile Ridge Road leads to the junction of Coyote Gulch and this route involves squeezing through a crack in the rim of the canyon—referred to as the Crack-in-the-Wall route—and then descending down the face of a 600 ft high sand dune. The sandy streambed of Coyote Gulch, typically just a few deep, provides a path for wading through the trees. Near the middle of the canyons length is Jacob Hamblin Arch—also known as Lobo Arch—which is large enough to reach under an overhang on the opposite side of the canyon. Further downstream within the canyon is Coyote Natural Bridge, a hole carved in a large sandstone fin. Still further downstream is Cliff Arch, a jug-handle style arch in the wall of the canyon. Finally, just outside the mouth of the canyon and high above the Escalante River, is Stevens Arch with an opening approximately 220 ft wide, there are also numerous small waterfalls and cascades in the canyon between Jacob Hamblin Arch and the confluence with the Escalante River. Some of these waterfalls can be climbed, but others must be bypassed. The northernmost branch of Coyote Gulch—called the Dry Fork—is one of the most popular destinations in the area, a short spur road leads off from the Hole-in-the-Rock Road to a trailhead above the wash. A brief descent to the canyon leads to several tributary slot canyons
42.
Rainbow Bridge National Monument
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Rainbow Bridge National Monument is administered by Glen Canyon National Recreation Area, southern Utah, United States. Rainbow Bridge is often described as the worlds highest natural bridge, the span of Rainbow Bridge was reported in 1974 by the Bureau of Reclamation to be 275 feet, but a laser measurement in 2007 has resulted in a span of 234 feet. At the top it is 42 feet thick and 33 feet wide, with a height of 290 feet Rainbow Bridge does indeed stand taller than either of its longer competitors, but it is outdone by Aloba Arch in Chad at 394 feet. The worlds tallest arch is Töshük Tagh, better known as Shiptons Arch, in China at an estimated 1,200 feet. Finally, Xianren Bridge, in Guangxi Province, China, with a span of about 295 feet, Rainbow Bridge is one of the most accessible of the large arches of the world. Rainbow Bridge is made from sandstone formed during the end of the Triassic, by the end of the Jurassic, the sea returned to cover these layers of sandstone and compressed them so tightly that they would persist until the present day. The previous course of the creek is visible above the bridge. Water flows back on itself at bends and wide spots, creating swirling eddies along the banks, as the creek flowed around Rainbow Bridge fin, these abrasive eddies formed on both the upstream and downstream sides and cut circular alcoves in the rock wall. The sediment in the creek eventually scoured the softer layers of sandstone away, located in the rugged, isolated canyons at the feet of Navajo Mountain, Rainbow Bridge was known for centuries by the Native Americans who have long held the bridge sacred. Ancient Pueblo People were followed later by Paiute and Navajo groups who named the bridge Nonnezoshe or rainbow turned to stone. Several Native American families still reside nearby, by the 1800s, Rainbow Bridge was probably seen by wandering trappers, prospectors, and cowboys. Not until 1909, though, was its existence publicized to the outside world, two separate exploration parties – one headed by University of Utah Dean Byron Cummings, and another by government surveyor, W. B. Douglass – began searching for the legendary span. Paiute guides Nasja Begay and Jim Mike led the way, along with trader and explorer John Wetherill, late in the afternoon of August 15, coming down what is now Bridge Canyon, the party saw Rainbow Bridge for the first time. The next year, on May 30,1910, U. S. President William Howard Taft used presidential proclamation to designate Rainbow Bridge National Monument, teddy Roosevelt and Zane Grey were among the first visitors to make the trek by foot and horseback from Oljeto or Navajo Mountain. They established a trail from the lodge to Cliff Canyon, then over Redbud Pass to Bridge Canyon, the 14-mile trip from the lodge to Rainbow Bridge could be made in one day by mule or horse. Bill and Catherine Wilson operated the lodge from 1928 to 1951, in 1942 Barry Goldwater acquired a half interest in the lodge. The main building at the site burned in August,1951, merritt and Winona Holloway operated the lodge in 1952, using a garage building as a dining hall. Miles Hedrick conducted some trips from the site for the next few years
43.
Sipapu Bridge
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Sipapu Bridge is a natural bridge or arch located in the Natural Bridges National Monument in the U. S. state of Utah. Sipapu was long reported to have a span of 268 feet by the National Park Service, a more accurate measurement obtained by laser survey in 2007 revealed the measurement to be a significant overstatement. The Natural Arch and Bridge Society has published a revised span of 225 feet, sipapu can be viewed from a roadside viewpoint but is best viewed from a short hiking trail that leads down to its base from the canyon rim. The name of the arch comes from the Hopi word sipapu, a word for a symbolic portal from which the first human ancestors emerged
44.
Guangxi
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Guangxi, officially the Guangxi Zhuang Autonomous Region, is a Chinese autonomous region in South Central China, bordering Vietnam. Formerly a province, Guangxi became a region in 1958. Guangxis location, in mountainous terrain in the far south of China, has placed it on the frontier of Chinese civilization throughout much of Chinas history, the current name Guang means expanse and has been associated with the region since the creation of Guang Prefecture in 226 AD. It was given provincial level status during the Yuan dynasty, but even into the 20th century it was considered an open, the abbreviation of the region is 桂, which comes from the name of the city of Guilin, the provincial capital during the Ming and Qing dynasties. Originally inhabited by a mixture of groups known to the Chinese as the Baiyue. In 214 BC, the Han Chinese general Zhao Tuo claimed most of southern China for Qin Shi Huang before the emperors death, the ensuing civil war permitted Zhao to establish a separate kingdom at Panyu known as Nanyue Southern Yue. The name Guangxi can be traced to the Expansive or Wide province of the Eastern Wu, Guilin formed one of its commanderies. Under the Tang dynasty, the Zhuang moved to support Piluoges Yi-ruled kingdom of Nanzhao in Yunnan, Guangxi was then divided into an area of Zhuang ascendancy west of Nanning and an area of Han ascendancy east of Nanning. After the collapse of the Southern Zhao, Liu Yan established the Southern Han in Xingwangfu, although this state gained minimal control over Guangxi, it was plagued by instability and annexed by the Song dynasty in 971. The name Guangxi itself can be traced to the Song, who administered the area as the Guangnanxi Circuit, harassed by both Song and the Jiaozhi in modern Vietnam, the Zhuang leader Nong Zhigao led a revolt in 1052 for which he is still remembered by the Zhuang people. His independent kingdom was short-lived, however, and the tattooed Song general Di Qing returned Guangxi to China, the Yuan dynasty established control over Yunnan during its conquest of the Dali Kingdom in 1253 and eliminated the Southern Song following the Battle of Yamen in 1279. Rather than ruling Lingnan as a territory or military district. The area nonetheless continued to be unruly, leading the Ming dynasty to employ the different local groups against one another, at the Battle of Big Rattan Gorge between the Zhuang and the Yao in 1465,20,000 deaths were reported. The Qing dynasty left the region alone until the imposition of rule in 1726. A Yao revolt in 1831 was followed by the Taiping Rebellion in 1850, the execution of St. Auguste Chapdelaine by local officials in Guangxi provoked the Second Opium War in 1858 and the legalization of foreign interference in the interior. Although Louis Brière de lIsle was unable to invade its depot at Longzhou, largely ineffective within Vietnam, it was still able to repulse the French from China itself at the Battle of Zhennan Pass on 23 March 1885. Following the Wuchang Uprising, Guangxi seceded from the Qing Empire on 6 November 1911, the Qing governor, Shen Bingdan, initially remained in place, but was subsequently removed by a mutiny commanded by General Lu Rongting. General Lus Old Guangxi clique overran Hunan and Guangdong as well, Zhuang loyalty made his Self-Government Army cohesive but reluctant to move far beyond its own provinces
45.
Sinkhole
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A sinkhole, also known as a cenote, sink, sink-hole, shakehole, swallet, swallow hole, or doline, is a depression or hole in the ground caused by some form of collapse of the surface layer. Most are caused by karst processes—for example, the dissolution of carbonate rocks or suffosion processes. Sinkholes vary in size from 1 to 600 m both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms, sinkholes may form gradually or suddenly, and are found worldwide. Sinkholes may capture surface drainage from running or standing water, but may form in high. Sinkholes that capture drainage can hold it in limestone caves. These caves may drain into tributaries of larger rivers, the formation of sinkholes involves natural processes of erosion or gradual removal of slightly soluble bedrock by percolating water, the collapse of a cave roof, or a lowering of the water table. Sinkholes often form through the process of suffosion, for example, groundwater may dissolve the carbonate cement holding the sandstone particles together and then carry away the lax particles, gradually forming a void. Occasionally a sinkhole may exhibit a visible opening into a cave below, sinkholes also occur in sandstone and quartzite terrains. As the rock dissolves, spaces and caverns develop underground and these sinkholes can be dramatic, because the surface land usually stays intact until there is not enough support. Then, a collapse of the land surface can occur. Sinkholes also form from human activity, such as the collapse of abandoned mines and salt cavern storage in salt domes in places like Louisiana, Mississippi, more commonly, sinkholes occur in urban areas due to water main breaks or sewer collapses when old pipes give way. They can also occur from the overpumping and extraction of groundwater, sinkholes can also form when natural water-drainage patterns are changed and new water-diversion systems are developed. Sinkholes tend to occur in karst landscapes, karst landscapes can have up to thousands of sinkholes within a small area, giving the landscape a pock-marked appearance. These sinkholes drain all the water, so there are only subterranean rivers in these areas, examples of karst landscapes with a plethora of massive sinkholes include Khammouan Mountains and Mamo Plateau. The largest known sinkholes formed in sandstone are Sima Humboldt and Sima Martel in Venezuela, some sinkholes form in thick layers of homogenous limestone. On the contact of limestone and insoluble rock below it, powerful underground rivers may form, in such conditions, the largest known sinkholes of the world have formed, like the 662-metre deep Xiaozhai Tiankeng, giant sótanos in Querétaro and San Luis Potosí states in Mexico and others. The state of Florida in the United States is known for having frequent sinkhole collapses, the Murge area in southern Italy also has numerous sinkholes. Sinkholes can be formed in retention ponds from large amounts of rain, an analysis of a case of sinkhole formation under a retention pond due to a large amount of rain can be seen in a sinkhole collapse study
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"Bridge, Natural". The American Cyclopædia. 1879.
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